After upgrade to ubuntu12.04 all down

after the upgrade to ubuntu12.04 the server started to do vlogger problem
and now it won't boot up.. i can access to it with rescue system but if i try to reboot it don't come up again please some one can help?

i can access to server in rescue but im unable to setup again the boot (i can mount the server in rescue... i see al files but unable to boot correctly) i tried all to install again grup ... but notting work